Shaft seal replacement

Motor, Motor Maintenance, Winches, Cooker, Heater, Fridge, Battery, Battery Charging, Shore Connection, Instruments, Autopilot, Anchor etc.
Post Reply
tpaliwoda
Posts: 215
Joined: Fri 03 Nov 06, 3:05
Your Country: USA, Raritan YC, Perth Amboy, New Jersey

Shaft seal replacement

Post by tpaliwoda »

Has anyone done this? I am thinking about doing it this spring but I would like to know some other peoples experiences.
Thanks
Ted
Ted Paliwoda
D'Fly 1000 ; HN #1
Nice Tri
Raritan YC, Perth Amboy, NJ, USA
Steve B.
Posts: 235
Joined: Thu 02 Nov 06, 1:58
Your Country: USA, Whidbey Island WA

Shaft seal replacement

Post by Steve B. »

Around 1988 I replaced the original packing type shaft seal on my previous monohull with a PSS Shaft Seal.
It was easy to do.
The hardest part was getting the flange off the shaft which bolts to the transmission.

About ten years later I replaced the bellows with the new more flexible design.
I did this replacement with the boat in the water.
The shaft was about 3 feet below the surface, but the bilge pump
took care of the water inflow during the bellows installation.

If you can get a PSS Shaft Seal to replace the brand in your DF,
I'd recommend it over the original type.

Steve B.
tpaliwoda
Posts: 215
Joined: Fri 03 Nov 06, 3:05
Your Country: USA, Raritan YC, Perth Amboy, New Jersey

Post by tpaliwoda »

Let's see if anyone has done this? I am going to change the Volvo seal this spring. Anyone done this and have some tips?

Thanks
Ted
Ted Paliwoda
D'Fly 1000 ; HN #1
Nice Tri
Raritan YC, Perth Amboy, NJ, USA
Oscar
Posts: 148
Joined: Tue 26 Aug 08, 23:10
Your Country: USA, North East

Post by Oscar »

I have.... in 95º weather and 120º in the engine room it took me 6 hours to get the coupling off......

Depending on how old, how much corrosion etc etc it can be a bear.

If it's bad:

Get a can of PB blaster and start spraying the you-know-what out of it NOW. Do it at least every 3-4 days for two weeks.
1990 Dragonfly 25 USA-54
Double Horizon
Posts: 440
Joined: Wed 09 May 07, 0:18
Your Country: USA

Post by Double Horizon »

tpaliwoda wrote:Let's see if anyone has done this? I am going to change the Volvo seal this spring. Anyone done this and have some tips?

Thanks
Ted
I changed the shaft seal on the 1000 with a PSS dripless seal. I don't remember the details but it was pretty straightforward.

I changed the cutlass bearing on the 1000 too. Don't ask -- that was awful. I hired a fiberglass guy to do it and I'm glad I did. He ground away the fiberglass around the aft end of the stern shaft tube but never did locate any set screws holding the original cutlass bearing. As far as he could tell it must have been epoxied in. It had to be cut out -- first a lengthwise cut from inside with a hacksaw blade, followed by a torch (to soften the epoxy) and hammering/prying with a chisel and long screw drivers to curl-in the cut edge and separate it from the bronze shaft tube. Then re-glassing around the end of the shaft tube to refinish properly.
Last edited by Double Horizon on Tue 27 Apr 10, 5:36, edited 2 times in total.
Larry - Former Owner DF-1200
Oscar
Posts: 148
Joined: Tue 26 Aug 08, 23:10
Your Country: USA, North East

Post by Oscar »

. As far as he could tell it must have been epoxied in.
Amazing.
1990 Dragonfly 25 USA-54
Double Horizon
Posts: 440
Joined: Wed 09 May 07, 0:18
Your Country: USA

Post by Double Horizon »

Oscar wrote:
Amazing.
Here's a shot of the finished result, before the new barrier coat went on.
http://www.nstsystems.com/multihulls/Pa ... utlass.jpg

Another issue that complicated the job was that the outer dimensions of the available 25mm cutlass bearings are larger than the inside dimension of the stern tube, so I had to buy the replacement and bring it to a machine shop to have a close-tolerance OD machined (on a lathe) that would be a perfect press-fit into the tube.
Larry - Former Owner DF-1200
tpaliwoda
Posts: 215
Joined: Fri 03 Nov 06, 3:05
Your Country: USA, Raritan YC, Perth Amboy, New Jersey

Post by tpaliwoda »

Oscar, Larry,
Thanks for the input.
I am just going to replace the shaft seal. I will most likely just use another Volvo seal.
Did you have to remove the existing shaft off the coupling to the transmission and slide it out through the stern?

Other than that it dosen't look to hard.

Thanks
Ted
Ted Paliwoda
D'Fly 1000 ; HN #1
Nice Tri
Raritan YC, Perth Amboy, NJ, USA
Oscar
Posts: 148
Joined: Tue 26 Aug 08, 23:10
Your Country: USA, North East

Post by Oscar »

Did you have to remove the existing shaft off the coupling to the transmission and slide it out through the stern?
I haven't seen this particular setup, but generally yes.
1990 Dragonfly 25 USA-54
Double Horizon
Posts: 440
Joined: Wed 09 May 07, 0:18
Your Country: USA

Post by Double Horizon »

tpaliwoda wrote:Oscar, Larry,
Thanks for the input.
I am just going to replace the shaft seal. I will most likely just use another Volvo seal.
Did you have to remove the existing shaft off the coupling to the transmission and slide it out through the stern?

Other than that it dosen't look to hard.

Thanks
Ted
Yes you would need to remove the shaft from the coupling, but you only need to have enough of a gap between shaft end and the coupling to slip the old shaft seal parts out, and the replacement parts in. No need to pull it completely out of the stern.
Larry - Former Owner DF-1200
Oscar
Posts: 148
Joined: Tue 26 Aug 08, 23:10
Your Country: USA, North East

Post by Oscar »

but you only need to have enough of a gap between shaft end and the coupling to slip the old shaft seal parts out, and the replacement parts in. No need to pull it completely out of the stern.
If, and that's a BIG IF, they want to come out. Often a puller is required....
1990 Dragonfly 25 USA-54
Double Horizon
Posts: 440
Joined: Wed 09 May 07, 0:18
Your Country: USA

Post by Double Horizon »

Oscar wrote:
If, and that's a BIG IF, they want to come out. Often a puller is required....
YES! It's a good practice to remove the shaft from the coupling every year, just for cleaning and to keep it free. When I pulled mine from the 1000 it looked like it hadn't been replaced in years, and the coupling was very rusted. I also removed the engine for refurbishment, and it's a good thing because the shaft had to come out through the engine compartment. When the mechanic got it back to his shop he put it on the floor-standing hydraulic press, which has a pressure gage -- he said it took about 14 tons of pressure to release the shaft from the coupling!
Larry - Former Owner DF-1200
tpaliwoda
Posts: 215
Joined: Fri 03 Nov 06, 3:05
Your Country: USA, Raritan YC, Perth Amboy, New Jersey

Post by tpaliwoda »

I will keep you all posted on this one. This weekend I will measure the size of the shaft - I do believe it is 25mm's but you know the old saying......
I will spray the crap out of the coupling, I always keep a can of that stuff on onboard.
Hopefully I will have the part next weekend.
No rush though, still waiting for the new water stays to come in.

Thanks again for the input.
Ted Paliwoda
D'Fly 1000 ; HN #1
Nice Tri
Raritan YC, Perth Amboy, NJ, USA
tpaliwoda
Posts: 215
Joined: Fri 03 Nov 06, 3:05
Your Country: USA, Raritan YC, Perth Amboy, New Jersey

Post by tpaliwoda »

Well we got it off today, no issues, pretty straight forward. Loosened the four bolts on the shaft coupling and slid right out.......


Now the yard mechanic comes over and we start talking about the job....this is where it gets good. He tells me that the shaft has to be totally aligned when going back in the coupling..... seemed pretty straight forward to me, I was just going to slide the new shaft seal only. Tighten the coupling and away we go! Is there any truth to this or is the yard guy looking for some extra cash?

Thanks
Ted
Ted Paliwoda
D'Fly 1000 ; HN #1
Nice Tri
Raritan YC, Perth Amboy, NJ, USA
Steve B.
Posts: 235
Joined: Thu 02 Nov 06, 1:58
Your Country: USA, Whidbey Island WA

Post by Steve B. »

I think he has a boat payment due.
Double Horizon
Posts: 440
Joined: Wed 09 May 07, 0:18
Your Country: USA

Post by Double Horizon »

tpaliwoda wrote:Well we got it off today, no issues, pretty straight forward. Loosened the four bolts on the shaft coupling and slid right out.......


Now the yard mechanic comes over and we start talking about the job....this is where it gets good. He tells me that the shaft has to be totally aligned when going back in the coupling..... seemed pretty straight forward to me, I was just going to slide the new shaft seal only. Tighten the coupling and away we go! Is there any truth to this or is the yard guy looking for some extra cash?

Thanks
Ted
I would not touch alignment unless you had a vibration problem before it came out. Otherwise all is good don't mess with it. The dripless shaft seal change should not affect alignment at all. :roll:
Larry - Former Owner DF-1200
tpaliwoda
Posts: 215
Joined: Fri 03 Nov 06, 3:05
Your Country: USA, Raritan YC, Perth Amboy, New Jersey

Post by tpaliwoda »

Shaft seal update - the PYI did not fit, to wide to fit into the bilge.
Back to the original Volvo seal!
Ted Paliwoda
D'Fly 1000 ; HN #1
Nice Tri
Raritan YC, Perth Amboy, NJ, USA
Oscar
Posts: 148
Joined: Tue 26 Aug 08, 23:10
Your Country: USA, North East

Post by Oscar »

Reference alignment......

Some people advocate doing an alignment every year, especially if the boat is on the hard in winter. Re-launch, wait for a week to let the boat shape settle down and align...... 4/1000 tolerance. Dial indicators for runout.

Vibration is something that creeps up on you. A little more is hardly noticed, then a little more, and a little more..... Not unbearable for the occupants, but more wear and tear on components. Over 6000 hours it adds up.

It's not hard to do, there's plenty of primers on the web.

All that said, you can put it back together and do it later this summer if it runs OK. Did you mark how the coupling was mounted, ie can you line up the holes the way they were?
1990 Dragonfly 25 USA-54
Post Reply